Pollution of the biosphere by heavy metals is a global hazard that has accelerated since the beginning of the industrial revolution. Toxic heavy metals are harmful to living organisms even at low concentrations wherea...Pollution of the biosphere by heavy metals is a global hazard that has accelerated since the beginning of the industrial revolution. Toxic heavy metals are harmful to living organisms even at low concentrations whereas heavy metals that are essential trace elements are required by plants at low concentrations but can become toxic at high concentrations. Heavy metals released from different sources accumulate in soil and, where bioavailability is high enough;can adversely affect soil biological functioning and other properties, leading to the loss of soil and ecosystem fertility and health. It is important that heavy metal contaminated sites are remediated as heavy metals do not decompose into less harmful substances like organic contaminants, and thus are retained in the soil. In this review, we survey and analysis our current knowledge and understanding of the abundance of heavy metals in soil, their phytoavailability, their toxicity, their uptake and transport, role of rhizobia and other microbes and overall rhizosphere processes.展开更多
A major environmental concern due to dispersal of industrial and urban wastes generated by human activities is the contamination of soil. The release of heavy metals into the terrestrial ecosystem is a major problem. ...A major environmental concern due to dispersal of industrial and urban wastes generated by human activities is the contamination of soil. The release of heavy metals into the terrestrial ecosystem is a major problem. Accumulation of heavy metals in environment and particularly in soil is a serious environmental concern, as the accumulated heavy metal ions can find their way into living organisms via contamination of ground water or food chain. This praxis urgently requires and demands governmental regulations in India. Two samples of sludge were collected from Banthar Industrial Pollution Control Company (BIPCC), UP State Industrial Development Corporation (UPSIDC), Leather Technology Park, Banthar, Unnao, India. In the present study, the phytoremediation potential of Catharanthus roseus, a valued medicinal plant, with respect to chromium has been analyzed. C. roseus was shown to absorb up to about 38% of the amount of Cr present in primary and secondary sludge amended soil through roots and accumulate it to about 22% in leaves. Effect of chromium concentration on the status of antioxidant enzyme peroxidase (POD) and detoxification enzyme glutathione-S-transferase (GST) from C. roseus leaves was also observed and determined. Increased expressions of POD and GST were observed on native PAGE under stress conditions as compared to control. C. roseus can well tolerate low amounts of chromium (and accumulate it to about 22% in leaves) and can, thus, prove useful in the reclamation and remediation of chromium contaminated soil and land.展开更多
Increasingly, as regulatory limits become more stringent, selenium has become a parameter of concern. Selenium is a naturally occurring element that is largely mobilized by anthropogenic activity such as mining for fu...Increasingly, as regulatory limits become more stringent, selenium has become a parameter of concern. Selenium is a naturally occurring element that is largely mobilized by anthropogenic activity such as mining for fuel and subsequent combustion, metal ore refining and processing, and agricultural irrigation. Of concern is removing selenium liquid matrices and immobilizing it from leachable solid matrices. Chemical reduction and stabilization using zero valent iron (ZVI) is applicable to both concerns. The solid matrix case study is applicable to ash ponds solids or industrial bag house dust solids. This paper presents data for treatment and stabilization of selenium within a solid matrix using ZVI. The methodology uses an aqueous mediate reaction to promote a stable solid matrix of non-leachable selenium. The paper describes matrix challenges and key variables that effected successful treatment. Testing with simulated and real bag house dust solids were used to establish data to support the permeance of the reaction. The data show that ZVI converts ionic selenium to a zero valent state in the solid matrix. It was also recognized that a fraction of ionic selenium may fail to react with the ZVI, but the results show that despite the presence of the unreacted ionic selenium, the toxicity characteristic leachate procedure (TCLP) results following treatment do not exceed the 1 mg/L hazardous waste criteria.展开更多
The application of mineral and organic phosphorus fertilizers to arable land has greatly increased crop yield to meet the world food demand.On the other hand,impurities in these fertilizers,such as heavy metals,are be...The application of mineral and organic phosphorus fertilizers to arable land has greatly increased crop yield to meet the world food demand.On the other hand,impurities in these fertilizers,such as heavy metals,are being added to agricultural soils,resulting both from the raw materials themselves and the processes used to obtain the final product.Cadmium,a non-essential and toxic heavy metal,has been found in relatively high amounts in common P fertilizers obtained from sediments.This metal poses a high risk for soil fertility,crop cultivation,and plants in general.Furthermore,human health might be compromised by the cadmium concentrations in agricultural and livestock products,due to the bioaccumulation effect in the food web.The accumulation in the different matrixes is the result of the high mobility and flexible availability of this harmful metal.This review summarizes risks to human health,the factors influencing cadmium movement in soils and crop uptake,as well as common plant responses to its toxicity.In addition,it summarizes cadmium balances in soils,trends,long-term experiments,and further studies.Cadmium inputs and outputs in arable soil,together with their calculated concentrations,are compared between two different regions:the European countries(in particular Germany)and China.The comparison appears useful because of the different proportions in the inputs and outputs of cadmium,and the diverse geographical,environmental and social factors.Moreover,these variables and their influences on cadmium contamination improve the understanding of the pollution from phosphate fertilizers and will help to establish future mitigation policies.展开更多
文摘Pollution of the biosphere by heavy metals is a global hazard that has accelerated since the beginning of the industrial revolution. Toxic heavy metals are harmful to living organisms even at low concentrations whereas heavy metals that are essential trace elements are required by plants at low concentrations but can become toxic at high concentrations. Heavy metals released from different sources accumulate in soil and, where bioavailability is high enough;can adversely affect soil biological functioning and other properties, leading to the loss of soil and ecosystem fertility and health. It is important that heavy metal contaminated sites are remediated as heavy metals do not decompose into less harmful substances like organic contaminants, and thus are retained in the soil. In this review, we survey and analysis our current knowledge and understanding of the abundance of heavy metals in soil, their phytoavailability, their toxicity, their uptake and transport, role of rhizobia and other microbes and overall rhizosphere processes.
文摘A major environmental concern due to dispersal of industrial and urban wastes generated by human activities is the contamination of soil. The release of heavy metals into the terrestrial ecosystem is a major problem. Accumulation of heavy metals in environment and particularly in soil is a serious environmental concern, as the accumulated heavy metal ions can find their way into living organisms via contamination of ground water or food chain. This praxis urgently requires and demands governmental regulations in India. Two samples of sludge were collected from Banthar Industrial Pollution Control Company (BIPCC), UP State Industrial Development Corporation (UPSIDC), Leather Technology Park, Banthar, Unnao, India. In the present study, the phytoremediation potential of Catharanthus roseus, a valued medicinal plant, with respect to chromium has been analyzed. C. roseus was shown to absorb up to about 38% of the amount of Cr present in primary and secondary sludge amended soil through roots and accumulate it to about 22% in leaves. Effect of chromium concentration on the status of antioxidant enzyme peroxidase (POD) and detoxification enzyme glutathione-S-transferase (GST) from C. roseus leaves was also observed and determined. Increased expressions of POD and GST were observed on native PAGE under stress conditions as compared to control. C. roseus can well tolerate low amounts of chromium (and accumulate it to about 22% in leaves) and can, thus, prove useful in the reclamation and remediation of chromium contaminated soil and land.
文摘Increasingly, as regulatory limits become more stringent, selenium has become a parameter of concern. Selenium is a naturally occurring element that is largely mobilized by anthropogenic activity such as mining for fuel and subsequent combustion, metal ore refining and processing, and agricultural irrigation. Of concern is removing selenium liquid matrices and immobilizing it from leachable solid matrices. Chemical reduction and stabilization using zero valent iron (ZVI) is applicable to both concerns. The solid matrix case study is applicable to ash ponds solids or industrial bag house dust solids. This paper presents data for treatment and stabilization of selenium within a solid matrix using ZVI. The methodology uses an aqueous mediate reaction to promote a stable solid matrix of non-leachable selenium. The paper describes matrix challenges and key variables that effected successful treatment. Testing with simulated and real bag house dust solids were used to establish data to support the permeance of the reaction. The data show that ZVI converts ionic selenium to a zero valent state in the solid matrix. It was also recognized that a fraction of ionic selenium may fail to react with the ZVI, but the results show that despite the presence of the unreacted ionic selenium, the toxicity characteristic leachate procedure (TCLP) results following treatment do not exceed the 1 mg/L hazardous waste criteria.
基金carried out as part of the project “Adaptation of Maize-based Food-feed-energy Systems to Limited Phosphate Resources” from the German-Chinese International Research Training Group 2366the support for this project provided by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)–328017493/GRK 2366Ten-Thousand Talent Program of China (Xuejun Liu)
文摘The application of mineral and organic phosphorus fertilizers to arable land has greatly increased crop yield to meet the world food demand.On the other hand,impurities in these fertilizers,such as heavy metals,are being added to agricultural soils,resulting both from the raw materials themselves and the processes used to obtain the final product.Cadmium,a non-essential and toxic heavy metal,has been found in relatively high amounts in common P fertilizers obtained from sediments.This metal poses a high risk for soil fertility,crop cultivation,and plants in general.Furthermore,human health might be compromised by the cadmium concentrations in agricultural and livestock products,due to the bioaccumulation effect in the food web.The accumulation in the different matrixes is the result of the high mobility and flexible availability of this harmful metal.This review summarizes risks to human health,the factors influencing cadmium movement in soils and crop uptake,as well as common plant responses to its toxicity.In addition,it summarizes cadmium balances in soils,trends,long-term experiments,and further studies.Cadmium inputs and outputs in arable soil,together with their calculated concentrations,are compared between two different regions:the European countries(in particular Germany)and China.The comparison appears useful because of the different proportions in the inputs and outputs of cadmium,and the diverse geographical,environmental and social factors.Moreover,these variables and their influences on cadmium contamination improve the understanding of the pollution from phosphate fertilizers and will help to establish future mitigation policies.
